D.2 Answers: RQs

Answers to exercises in Sect. 2.13.

Answer to Exercise 2.1: See Table D.1.
TABLE D.1: Terms matched with their operational definitions
Term Definition
Rainwater Rainwater from a rainwater collection tank on your property
Bottled Water sold in bottles by food companies that is widely available to the public for purchase and consumption
Tap Water you presently use throughout your dwelling (home)
Recycled Highly purified wastewater deemed by scientists as safe for human consumption
Desalinated Highly purified seawater deemed by scientists and public health officials as safe for human consumption
Answer to Exercise 2.2: 1. P: USC students. 2. O: Resting diastolic blood pressure. 3. C: between students who regularly drive to USC and those who regularly ride their bicycles. 4. No intervention. 5. Relational. 6. What is meant by ‘regularly’; ‘USC student’ (all campuses? undergraduate and postgraduate? full-time and part-time?). 7. Resting diastolic blood pressure; whether they regularly drive to USC or regularly ride their bicycles.
Answer to Exercise 2.3: 1. P: Children aged under 3 in a Peruvian peri-urban community; O: diarrohea status; C: nutritional status; No intervention. 2. Hard to be sure; perhaps something like: ‘In children aged under 3 in a Peruvian peri-urban community, is there a a relationship between diarrohea status and nutritional status?’ 3. Relational. 4. How is ‘diarrohea status’ measured? Likewise, how is ‘nutritional status’ measured? There are probably others. 5. Response: diarrohea status; explanatory: nutritional status.

Answer to Exercise 2.4: Recall that the outcome is used to describe a group (the population), not the individuals.

1. The percentage of vehicles that crash. 2. The average jump height. 3. The average number of tomatoes per plant. 4. The percentage of people who own a car.

Answer to Exercise 2.5: Recall that the explanatory variable is what is actually measured on the individuals in the population.

1. The type of car fuel. 2. The type of coffee. 3. The dose of iron supplement. 4. The diet.
Answer to Exercise 2.6: 1. Does have a comparison (between a group of people in winter, and a different group of people in summer). The outcome is ‘the percentage of people wearing hats.’ 2. Does not have a comparison. Two subsets of the population are not being compared: instead, each person is measured twice. So an Outcome may be ‘average change in cholesterol levels.’ 3. Does not have a comparison. Two subsets of the population are not being compared: instead, each person gets two measurements. So an Outcome may be ‘average difference between right- and left-leg balance times.’ 4. Does have a comparison: The three subsets of the population are being compared: the three groups of tomato plants. The Outcome is ‘average yield’ (which could be measured in kg/plant, tomatos/plant, kg/hectare, etc).

Answer to Exercise 2.7: The unit of observation is the animal: The animals, for example, are weighed.

The unit of analysis is the pen, as the food is allocated to the animals in the whole pen. In addition, the animals in the same pen are not independent: they compete for the same space, food, resources, and would all have similar environments that they share.

Answer to Exercise 2.8: The population surely is not 10 adults; that sounds like the sample. It does not make clear how many fonts are being compared (or which fonts are being used).

Perhaps try this:

Among Australian adults, is the time taken to read a passage of text different when Arial font is used compared to Times Roman font?

Answer to Exercise 2.9: The RQ is about comparing groups, so it should talk about the average lung capacity of males and females. Perhaps:

Of students that study at USC, Sippy Downs, do males have a larger average lung capacity than females?